Ablation and Precursor Formation in Copper Wire-Array and Liner $Z$-Pinches

Blesener, I. C.; Kusse, B. R.; Blesener, K. S.; Greenly, J. B.; Hammer, D. A.

doi:10.1109/tps.2012.2220985

Cited by 6 publications

(4 citation statements)

References 26 publications

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“…Lebedev et al 1999Lebedev et al , 2001Alexandrov et al 2002;Cuneo et al 2005;Blesener et al 2012a;Swadling et al 2013a,b). However, with the exception of some liner ablation experiments undertaken on the COBRA facility (Blesener et al 2012b), early-time liner behaviour has not. We can expect significant differences in the dynamics of liner implosions because of the increased mass, and the change in the azimuthal mass distribution and magnetic field structure.…”

Section: The Response Of Cylindrical Metallic Liners To Pulsed Currentmentioning

confidence: 99%

Cylindrical liner Z-pinch experiments for fusion research and high-energy-density physics

et al. 2015

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A gas-filled cylindrical liner z-pinch configuration has been used to drive convergent radiative shock waves into different gases at velocities of 20–50 km s−1. On application of the 1.4 MA, 240 ns rise-time current pulse produced by the Magpie generator at Imperial College London, a series of cylindrically convergent shock waves are sequentially launched into the gas-fill from the inner wall of the liner. This occurs without any bulk motion of the liner wall itself. The timing and trajectories of the shocks are used as a diagnostic tool for understanding the response of the liner z-pinch wall to a large pulsed current. This analysis provides useful data on the liner resistivity, and a means to test equation of state (EOS) and material strength models within MHD simulation codes. In addition to providing information on liner response, the convergent shocks are interesting to study in their own right. The shocks are strong enough for radiation transport to influence the shock wave structure. In particular, we see evidence for both radiative preheating of material ahead of the shockwaves and radiative cooling instabilities in the shocked gas. Some preliminary results from initial gas-filled liner experiments with an applied axial magnetic field are also discussed.

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Section: The Response Of Cylindrical Metallic Liners To Pulsed Currentmentioning

confidence: 99%

Cylindrical liner Z-pinch experiments for fusion research and high-energy-density physics

et al. 2015

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“…If the damper resistivity is large, then most of the current flows inside the sample and generate a coronal plasma which is difficult to compress, leading to smaller stagnation pressures. Since large current densities can also generate electrothermal instabilities [3], the presence of the damper slow down their growth.…”

Section: Initial Conditionsmentioning

confidence: 99%

The Generation of Warm Dense Matter Using a Magnetic Anvil Cell

Gourdain

Sefkow

Seyler

2018

IEEE Trans. Plasma Sci.

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Warm dense matter is present at the heart of gas giants and large exo-planets. Yet, its most basic properties are unknown and limit our understanding of planetary formation and evolution. In this state, where pressure climbs above 1 Mbar, matter is strongly coupled and quantum degenerate. This combination invalidates most theories capable of predicting the equation of state, the viscosity or heat conductivity of the material. When such properties are missing, understanding planetary evolution becomes an arduous endeavor. Henceforth, research in this field is actively growing, using high power laser or heavy ion beams to produce samples dense enough to overcome the 1 Mbar limit. These samples are not actively confined and tend to expand rapidly, precluding the existence of any thermodynamically stable equilibrium.However, a mega-ampere-class pulsed-power generator can produce confined matter in the Mbar range, providing two conditions are being met. First, the sample needs to be compressed cylindrically, to maximize magnetic pressure (compared to slab compression). Second, a damper must be used to preclude the formation of a corona around the sample. This corona robs the main sample from valuable current and limits the homogeneity of the compression. According to numerical simulations, the setup proposed here, and called a magnetic anvil cell, can reach pressure on the order of 1 Mbar using a megaampere pulsed power driver. These samples span several millimeters in length. Unlike diamond anvil cell, which pressure is limited below 1 Mbar due to materials strength, the magnetic anvil cell has virtually no pressure limit. Further, the current heats the sample to several eV, a temperature well beyond diamond anvil cell capabilities.Index Terms-Warm dense matter, Z-pinch, pulsed-power generator, diamond anvil cell S. B. Author, Jr., was with Rice University, Houston, TX 77005 USA. He is now with the

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“…Also, it was observed that a liner irradiates approximately half the x-ray power of wire-arrays with comparable x-ray yields [7]. At the Cornell Beam Research Accelerator (COBRA) facility with ∼ 1 MA peak current, Blesener et al found that the nearperfect liners had uniform and reduced ablation on the inner surface, leading to a greatly reduced precursor mass compared with wire arrays [11,12]. Plasma initiation studies that taking an intentionally controlled current contact and the initial liner surface structure into account were performed by Bott-Suzuki et al [13] and Shelkovenko et al [14] respectively on the same machine.…”

Section: Introductionmentioning

confidence: 99%

Pulsed-power-driven cylindrical aluminium liner implosions with a high aspect ratio at an 8 MA facility

Lü¹,

Yan²,

Meng³

et al. 2020

Nucl. Fusion

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First experimental investigations of foil aluminium liner implosions with a high aspect ratio of ∼ 103 at an 8 MA pulsed-power facility in China, motivated by possible application for magneto-inertial fusion, will be reported. Key diagnostics including UV cameras, micro-magnetic probes and x-ray pinhole imaging systems were fielded. Quasi-monochromatic UV images and optical streak data showed localized plasma formation at breakdown positions, suggesting that vacuum gaps in contact play a crucial role in long-time and non-uniform initiation. In liner ablation, quasi-periodic striation patterns were directly observed in UV self-emission images and were found to be azimuthally correlated with Rayleigh–Taylor instabilities. An m ≠ 0 azimuthal helical mode was obtained for the unmagnetized liner, which could be attributed to the large surface roughness that may act as an inherently and randomly seeded instability. Precursor plasma formation was confirmed by the observed x-ray emission on-axis at −70 ns by the end-on x-ray framing camera. Further quantitative current measurements taken by micro magnetic probes suggested that the current division due to precursor plasma was approximately 20% of the load current at −66 ns. Side-on imaging diagnostics indicated an evident liner implosion, however with a relatively low convergence ratio of ∼ 3.2 at stagnation. For the observed emission rings with much faster velocity in end-on x-ray images, possible mechanisms were discussed.

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Ablation and Precursor Formation in Copper Wire-Array and Liner $Z$-Pinches

Cited by 6 publications

References 26 publications

Cylindrical liner Z-pinch experiments for fusion research and high-energy-density physics

Cylindrical liner Z-pinch experiments for fusion research and high-energy-density physics

The Generation of Warm Dense Matter Using a Magnetic Anvil Cell

Pulsed-power-driven cylindrical aluminium liner implosions with a high aspect ratio at an 8 MA facility

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